文档介绍：Chapter 2.
SAT Save File Format
Topic: SAT Save and Restore
ACIS can store modeling information in external files, called save files. These files have an
open format so that external applications, even those not based on ACIS, can have access to
the ACIS geometric model.
The basic information needed to understand the ACIS file format (focusing on the reading, or
restore, operation), includes the structure of the save file format, how data is encapsulated, the
types of data written, and subtypes and references.
Save File Types
Topic: *SAT Save and Restore
ACIS supports two kinds of save files, SAT and SAB, which stand for “Standard ACIS Text”
and “Standard ACIS Binary”, respectively. Although one is ASCII text and the other is binary
data, the model data information stored in the two formats is identical, so the term SAT file is
generally used to refer to either (when no distinction is needed).
SAT files are ASCII text files that may be viewed with a simple text editor. A SAT file
contains carriage returns, white space and other formatting that makes it readable to the
human eye. A SAT file has a .sat file extension.
SAB files cannot be viewed with a simple text editor and are meant pactness and not
for human readability. A SAB file has a .sab file extension. A SAB file uses delimiters
between elements and binary tags, without additional formatting.
The binary formats supported are:
int.......... 4--byte plement (as long)
long......... 4--byte plement
double....... 8--byte IEEE
char......... 1--byte ASCII
SAT Format D
where “byte” is eight bits, and files are considered to be byte strings. For multi--byte data
items, byte order normally just matches that of the processor being used, but a specific order
may be imposed piling with the preprocessor macro BIG_ENDIAN or
LITTLE_ENDIAN defined.
Structure of the Save File
Topic: SAT Save and Restore
A save file contains:
D Three-line header
D Entity records,